1. Field of the Invention
This invention relates to attachments to tractors or other vehicles. In greater particularity it relates to the use of attachments which permit a given implement to be moved in several ways including being displaced sideways without a centrally attached pivot point. In further detail, the invention can be mounted either as a front end or back end device.
2. Description of the Prior Art
The use of implements such as plows, buckets, boxes, and so forth on vehicles permit the moving of objects, such as dirt, faster and easier than direct human labor such as shoveling.
Prior art devices have consistently been limited to narrowly defined applications. Changing the tilt, pitch, height, and lateral angle are exceptionally useful applications for various tasks. The problem has been that different tasks have required changing implements. A variety of techniques have been tried to allow the attachment method to extend the range of uses of the implement. Tilt means one side of the implement is higher than the other side. Pitch refers to whether the implement leans forward or back. Height refers to how high the entire implement is picked up. Lateral angle refers to the twist of the implement.
By way of example, a snow plow will be used as an example of an implement. Height controls whether the plow is on the ground or above. Lateral angle is usually fixed at other than 90.degree. to the direction of movement so the snow slides to one side of the road as the vehicle goes forward. Pitch is usually a design feature of the plow so that it slopes back near the road surface and then curves over to prevent rising snow from going over the top of the plow. Tilt is usually fixed at 0.degree. to the level because the plow does not desire digging into the road surface. As can be readily seen, for different implements the criteria for each of these settings may vary.
A significant problem for changing the lateral angle is that if the implement is moveable, it is difficult to assure a return to a set position, such as perpendicular to the movement of the vehicle.
Prior art devices have been structurally limited because the movement areas must bear the bulk of the weight of the implement and can be easily damaged while in use.
Prior art devices also rely on a central attachment point and rely on this location to define movement, load and so forth. Because of pivoting about a central point, as this point wears it is difficult to guarantee the implement, such as a blade, can be set perpendicular to the direction of the vehicle.
Techniques are know which allow some displacement about the central attachment point. This technique makes such side shift one sided and the entire vehicle with attachments must turn around and travel the opposite direction if the shift is required to the opposite side. Side shift is highly useful as approaches along buildings, for example, have to deal with awnings, eaves and so forth which extend from the building. A common result is that there are areas where removal by hand labor is still required for a large variety of tasks.
The structural mounting to vehicles has depended on the frame construction of the vehicle to be used. Some vehicles have frames that may be used to attach implements by bolting or welding. Some vehicles, some tractor styles for example, only offer an anchor post. While an anchor post may be ideal for a towing hitch, it does cause problems for devices requiring support at two or more locations. Chains have been used to cross-link in such cases, but while chains prevent points from pulling apart, chains sag if compression is presented.